[Amps] Grounded B+ amplifier

R.Measures r at somis.org
Fri Feb 27 09:37:11 EST 2004

>On Thursday 26 February 2004 17:33, Bill Turner wrote:
>> Years ago I recall reading about an amplifier where the B+ supply was
>> grounded and the cathode was "hot" with the B- supply.  I'm wondering if
>> that might have some advantages for high power amplifiers.
>> Specifically, the pi-network output could be simplified by eliminating
>> the plate choke.  Here's how the output would look:
>> http://www.dslextreme.com/users/teeaye/B+.jpg
>> Believe it or not, this is a pi-network output circuit, just redrawn.
>> The same component values would be used as with a conventional circuit.
>Doesn't it do a lovely job of offering an alternative insight into how a pi 
>network matches between the antenna and plate. The load control is the lower 
>capacitor and provides a variable 'tap' up and down the tuned circuit.
**  Indeed, Steve, indeed.  It also might help folks understand why such 
a circuit resonates c. 10% lower than the operating frequency. 

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